1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu What is a Biome? Biomes are large regions characterized by a specific type of climate and plant and animal communities. Each biome is made up of many individual ecosystems. Chapter 6 Section 1 What Is a Biome?

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Biomes and Vegetation Biomes are described by their vegetation because plants that grow in an area determine the other organisms that can live there. Plants have adaptations which include size, shape, and color that help them to survive. –For example, plants in the tundra tend to be short because they cannot obtain enough water to grow larger. Chapter 6 Section 1 What Is a Biome?

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Biomes and Climate Climate is the average weather conditions in an area over a long period of time. Climate is the main factor is determining which plants can grow in a certain area, which in turn defines the biome. Temperature and precipitation are the two most important factors that determine a region’s climate. Chapter 6 Section 1 What Is a Biome?

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Temperature and Precipitation Most organisms are adapted to live within a particular range of temperatures. Precipitation also limits the organisms that can be found in a biome because the bigger the organism, the more water it needs. The higher the temperature and precipitation are, the taller and denser the vegetation is. Chapter 6 Section 1 What Is a Biome?

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Latitude and Altitude Latitude is the distance north or south from the equator, and is expressed in degrees. Altitude is the height of an object above a reference point, such as sea level or the Earth’s surface. Climate gets colder as latitude and altitude increase. This is why it gets colder as you move further up a mountain. As latitude and altitude increase, biomes and vegetation change. Chapter 6 Section 1 What Is a Biome?

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Latitude and Altitude Trees of tropical rainforests grow close to the equator, while mosses/lichens of tundras grow close to the poles. The temperate region includes biomes such as temperate forests and grasslands, which have moderate temperatures and fertile soil that is ideal for agriculture. Chapter 6 Section 1 What Is a Biome?

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Tropical Rain Forests Tropical rain forests are forests/jungles near the equator, characterized by large amounts of rain, little variation in temperature, and the greatest diversity of organisms. They help regulate world climate and play vital roles in the nitrogen, oxygen, and carbon cycles. They are humid, warm, and get strong sunlight which allows them to maintain a fairly constant temperature ideal for a wide variety of plants and animals. Chapter 6 Section 2 Forest Biomes

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Nutrients in Tropical Rain Forests Most nutrients are within the plants, not the soil, so when forests are cleared for agriculture, the infertile soil cannot support the growth of crops. Decomposers on the rain-forest floor or on trees break down dead organisms and return the nutrients to the soil, but plants quickly absorb the nutrients. Many of the trees form above ground roots called buttresses or braces that grow sideways from the tree to provide it with extra support in the thin soil. Chapter 6 Section 2 Forest Biomes

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Layers of the Rain Forest emergent layer is the top foliage layer in a forest where the trees extend above surrounding trees. canopy is the layer of treetops that shade the forest floor, and is the primary layer of the rain forest. –Epiphytes are plants that use another plant for support but not for nourishment; located on high trees in the canopy. understory are plants with large flat leaves that grow on the forest floor capture the small amount of light that penetrates. Chapter 6 Section 2 Forest Biomes

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Species Diversity The diversity of rain-forest vegetation has led to the evolution of a diverse community of animals. Most rainforest animals are specialists that use specific resources in particular ways to avoid competition and have adapted amazing ways to capture prey and avoid predators. Insects use camouflage to avoid predators and may be shaped like leaves or twigs. Chapter 6 Section 2 Forest Biomes

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Threats to Rain Forests Every minute, every day, 100 acres of tropical rainforest are cleared for logging operations, agriculture, and oil exploration. Exotic-pet trading robs the rain forests of rare and valuable plant and animal species only found there. Habitat destruction occurs when land inhabited by an organism is destroyed or altered, which leaves the organism is at risk of disappearing. About 50 million native peoples live in tropical rain forests and are also threatened by habitat destruction. Because they obtain nearly everything they need from the forest, the loss of their habitat could force them to leave their homes and move into cities. Chapter 6 Section 2 Forest Biomes

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Temperate Forests Temperate rain forests are forests communities that are characterized by cool/moderate year round temps, humid weather and abundant rainfall Tree branches are draped with mosses, tree trunks are covered with lichens, and the forest floor is covered with ferns. They occur in North America, Australia, and New Zealand, and are dominated by evergreen trees such as the Douglas fir and Sitka spruce. Chapter 6 Section 2 Forest Biomes

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Temperate Deciduous Forests Temperate deciduous forests are forests characterized by trees that shed their leaves in the fall, and located between 30º and 50º north latitude. The range of temperatures can be extreme, with hot summer temperatures and winter temperatures falling below freezing. They receive 75 to 125 cm of precipitation annually which helps to decompose dead organic matter contributing to the rich soils of the forest. Chapter 6 Section 2 Forest Biomes

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Plants of Deciduous Forests Plants in the deciduous forests grow in layers with tall trees, such as birch, dominating the canopy while shrubs cover the understory. –more light reaches deciduous forest floors than rain forests floors allowing more plants to grow. Temperate-forest plants are adapted to survive seasonal changes. In the fall and winter, trees shed their leaves and seeds go dormant under the insulation of the soil. With the returning warmth in the spring, the trees grow new leaves and seeds germinate. Chapter 6 Section 2 Forest Biomes

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Animals of Deciduous Forests The animals of temperate deciduous forests are adapted to use the forest plants for both food and shelter. Birds cannot survive the harsh winter of the deciduous forests so each fall they fly south for warmer weather and better availability of food. Mammals and insects, reduce their activity so that they do not need as much food for energy, enabling them to survive the winter. Chapter 6 Section 2 Forest Biomes

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Taiga The taiga is the region of evergreen, coniferous forest below the arctic and subarctic tundra regions. The taiga has long winters and little vegetation. The growing season can be as short as 50 days with most plant growth occurring during the summer months because of nearly constant daylight and larger amounts of precipitation. Chapter 6 Section 2 Forest Biomes

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Plants of the Taiga A conifer is a tree that has seeds that develop in cones. Their leaves’ arrow shape and waxy coating helps them to retain water in the winter. The conifer’s shape also helps the tree shed snow to the ground and not get weighed down. Conifer needles contains substances that make the soil acidic when they fall to the ground preventing plants from growing on the floor. Also, soil forms slowly in the taiga because the climate and acidity slow decomposition. Chapter 6 Section 2 Forest Biomes

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Animals of the Taiga The taiga has many lakes and swamps that in the summer attract birds that feed on insects. To avoid the harsh winters, birds migrate, while some year round residents, such as shrews, burrow underground for better insulation. Snowshoe hares have adapted to avoid predation by shedding their brown summer fur and growing white fur that camouflages them in the winter snow. Chapter 6 Section 2 Forest Biomes

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Savannas Savannas are plains full of grasses and scattered trees and shrubs that are found in tropical and subtropical habitats. Found mainly in regions with a dry climate, such as East Africa and western India. Although savannas receive little precipitation throughout the year, they do have a wet season and a dry season. Many animals are only active during the wet season. Grass fires help to restore nutrients to the soil during the dry season. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Plants of the Savanna Because most of the rain falls during the wet season, plants must be able to survive prolonged periods without water. Some plants have large horizontal root systems to help them survive the dry season. These roots also enable the plant to grow quickly after a fire. The grasses also have coarse vertical leaves that expose less surface area to help conserve water, while some trees shed their leaves. Almost all have thorns for protection from herbivores. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Animals of the Savanna Grazing herbivores, like the elephant, have adopted migratory ways of life, following the rains to areas of new grass and fresh watering holes. Predators also stalk these animals for food. Many savanna animals give birth only during the rainy season, when food is abundant and the young are more likely to survive. Some species of herbivores reduce competition for food by eating vegetation at different heights than other species do. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Temperate Grasslands Temperate grasslands are communities that are dominated by grasses, have few trees, and have hot summers and cold winters, with moderate rainfall. Temperate grasslands have the most fertile soil of any biome. Mountains often play a crucial role in maintaining grasslands as rain clouds from the west are blocked. However, rainfall does increase as you move eastward, allowing taller grasses to grow. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Plants of Temperate Grasslands The root system of prairie grasses forms dense layers that survive drought and fire allowing the plants to come back from year to year. Few trees survive on the grasslands because of the lack of rainfall, fire, and the constant winds. The amount of rainfall in the area determines root depth and grass height. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Animals of Temperate Grasslands Some grazing animals, such as the bison and pronghorn antelope, have large, flat teeth for chewing the coarse prairie grasses. Other grasslands animals, such as prairie dogs, owls, and badgers, live protected in underground burrows that protect them from predators on the open grasslands. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

25. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Threats to Temperate Grasslands Farming and overgrazing have changed the grasslands. –Grain crops cannot hold the soil in place because the roots of crops are shallow and plowing is often, so soil erosion eventually occurs. –Erosion is also caused as the grasses are constantly eaten and trampled. –Constant use can change the fruitful grasslands into desert like biomes. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

26. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chaparral Chaparral is a type of temperate woodland biome with vegetation that includes broad leafed evergreen shrubs and is located in areas with hot, dry summers and mild, wet winters. Chaparrals are located in the middle latitudes, about 30° north and south of the equator. Chaparrals are located primarily in coastal areas that have Mediterranean climates. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

27. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Plants of the Chaparral Most chaparral plants are low-lying, evergreen shrubs and small trees that tend to grow in dense patches. These plants have small, leathery leaves that contain oils that promote burning, allowing natural fires to destroy competing trees. Chaparral plants are well adapted to fire and can resprout from small bits of surviving plant tissue. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

28. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Animals of the Chaparral A common adaptation of chaparral animals Is camouflage, shape or coloring that allows an animal to blend into its environment. –Animals such as quail, lizards, chipmunks, and mule deer have a brownish gray coloring that lets them move through the brush without being noticed. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

29. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Threats to the Chaparral Worldwide, the greatest threat to chaparral is human development. Humans tend to develop lands of the chaparral for commercial and residential use because these biomes get a lot of sun, are near the oceans, and have a mild climate year round. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

30. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Deserts Deserts are regions that have little or no vegetation, long periods without rain, and extreme temperatures. Deserts are often located near large mountain ranges because mountains can block the passage of moisture-filled clouds, limiting precipitation. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

31. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Plants of the Desert All desert plants have adaptations for obtaining and conserving water. Plants called succulents, such as cactus, have thick, fleshy stems and leaves with a waxy coating to prevent water loss, while sharp spines on the plant keep animals away. Many plant roots spread out just under the surface to absorb as much rain as possible. When conditions are too dry, these plants die and drop their seeds that stay dormant until the next rainfall. Then, new plants quickly germinate, grow, and bloom before the soil becomes dry again. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

32. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Animals of the Desert Animals of the desert have adapted many different ways to prevent water loss. –Reptiles have thick, scaly skin that prevents water loss. –Amphibians survive by estivating, or burying themselves in the ground and sleeping through the dry season. –Insects are covered with body armor that helps them retain water. Most desert animals are nocturnal, meaning they are active mainly at night or dusk when it is cooler. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

33. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Tundra The tundra is a treeless plain that is located in the Arctic or Antarctic, characterized by cold winter temperatures, short, cool summers, and vegetation that consists of grasses, lichens, and perennial herbs. Summers are short in the tundra, so only the top few centimeters of soil thaw. Permafrost is the permanently frozen layer of soil or subsoil and can be found in the tundra regions. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

34. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Vegetation of the Tundra Mosses and lichens, which can grow without soil, cover vast areas of rocks in the tundra. The soil is thin, so plants have wide shallow roots to help anchor them against the icy winds. Most flowering plants are short, which keeps them out of the wind and helps them absorb heat from the sunlit soil. Woody plants and perennials have evolved dwarf forms that grow flat along the ground. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

35. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Animals of the Tundra Millions of migratory birds fly to the tundra to breed in the summer when food is abundant. Caribou migrate throughout the tundra in search of food and water. Hunters such as wolves prey on migratory caribou, deer, and moose. Rodents stay active, but burrow underground to avoid the cold. Other year-round residents, such as arctic foxes, lose their brown summer coat for white fur that camouflages them with the snow. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes

36. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Threats to the Tundra The tundra is one of the most fragile biomes on the planet. The food chains are relatively simple so they are easily disrupted. Until recently these areas have been undisturbed by humans. But oil was located in parts of the tundra, and oil exploration, extraction, and transport has disrupted many tundra habitats. Pollution caused by spills or leaks of oil and other toxic materials may also poison the food and water sources of organisms of the tundra. Chapter 6 Section 3 Grassland, Desert, and Tundra Biomes